1. Field of the Invention
This invention relates to video cassette duplication, and in particular to the commercial preparation of multiple video tape copies of program materials, such as movies, for rental or sale.
2. Description of the Prior Art.
With the advent of popular, affordable home video cassette recording machines the VCR, a new market has emerged for pre-recorded audio visual programs such as movies or music videos. Specifically, many consumers who own VCRs desire to rent pre-recorded movies and even collect a home library of audio visual programs for private viewing at convenient times. Although some consumers prefer to create their own home libraries by recording off the air, many VCR owners prefer to purchase or rent a professionally recorded copy of the programming material of particular interest to them, such as classic movies, plays, musical performances and the like which are unavailable on standard broadcast television.
Therefore, as a consequence of the availability of VCRs, the demand for high quality copies of original programming material in video tape cassette form has drastically and rapidly increased. Prior to the present invention, video cassette copies of original programming materials have been prepared by connecting a master source of the programming signals, typically a reel to reel tape recorder, to a multiplicity of "slave" commercial grade video cassette recorder. Each of the "slave" recorders are loaded with a cassette containing a suitable length of raw or blank video tape. Typically, the "slave" recorders are manually operated by individual operators in synchronism with the master source and monitored until the end of the programming material and substantially the full length of tape is recorded. After each cassette has been thus recorded, it is removed and a fresh blank cassette is installed in each "slave" unit. The master tape is reset to start a fresh run of the source programming material to make another "batch" of copies. The individual recorded cassette copies are then individually boxed and sent for distribution.
This prior art technique for preparing copies of original audio visual programming materials suffers from several disadvantages. Firstly, commercially available video tape cassettes are loaded with a supply of video tape sufficient to provide generally predetermined time increments of recording capability depending upon the speed of recording. The magnitude of these increments varies from as little as thirty minutes to as much as six hours, usually in one half hour increments. The actual incremental time value of the amount of tape in a particular cassette is partially a function of the actual amount of tape and partially a function of the recording speeds provided by the available consumer video cassette recorders. Except in rare instances, the actual recording time represented by the amount of tape in a given cassette never matches the length of the programming materials to be recorded. As a consequence, only a rough match can be made between the length of the blank video tape and the programming materials, with the result that often video tape is wasted in the cassette.
In addition, the cleanliness of video tape used in blank video cassettes varies widely depending upon the storage conditions as well as other factors, and may vary along the length of the tape within a given cassette. Since professionally recorded copies must have the highest fidelity in order to be acceptable in the marketplace, many defective cassettes may have to be discarded. This is very time consuming and wasteful, since rejected cassettes must be either discarded or sold as used merchandise.
Also, the preparation of copies by the use of "slave" cassette recorders greatly increase the labor cost involved, because each machine must be unloaded, loaded, and restarted simultaneously to make a second "batch" of copies. Typically, one hour of recording time is lost during this change over period.